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1.
PLoS Pathog ; 20(9): e1012533, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39231185

RESUMO

The body temperature of Warm-blooded hosts impedes and informs responses of bacteria accustomed to cooler environments. The second messenger c-di-GMP modulates bacterial behavior in response to diverse, yet largely undiscovered, stimuli. A long-standing debate persists regarding whether a local or a global c-di-GMP pool plays a critical role. Our research on a Stenotrophomonas maltophilia strain thriving at around 28°C, showcases BtsD as a thermosensor, diguanylate cyclase, and effector. It detects 37°C and diminishes c-di-GMP synthesis, resulting in a responsive sequence: the periplasmic c-di-GMP level is decreased, the N-terminal region of BtsD disengages from c-di-GMP, activates the two-component signal transduction system BtsKR, and amplifies sod1-3 transcription, thereby strengthening the bacterium's pathogenicity and adaptation during infections in 37°C warm Galleria mellonella larvae. This revelation of a single-protein c-di-GMP module introduces unrecognized dimensions to the functional and structural paradigms of c-di-GMP modules and reshapes our understanding of bacterial adaptation and pathogenicity in hosts with a body temperature around 37°C. Furthermore, the discovery of a periplasmic c-di-GMP pool governing BtsD-BtsK interactions supports the critical role of a local c-di-GMP pool.


Assuntos
Proteínas de Bactérias , GMP Cíclico , Infecções por Bactérias Gram-Negativas , Stenotrophomonas maltophilia , Stenotrophomonas maltophilia/metabolismo , GMP Cíclico/análogos & derivados , GMP Cíclico/metabolismo , Animais , Infecções por Bactérias Gram-Negativas/microbiologia , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Transdução de Sinais , Temperatura Corporal/fisiologia , Regulação Bacteriana da Expressão Gênica , Fósforo-Oxigênio Liases/metabolismo , Fósforo-Oxigênio Liases/genética
2.
Plant J ; 119(5): 2273-2287, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39012276

RESUMO

The cutting technique is extensively used in tea breeding, with key emphasis on promoting the growth of adventitious roots (ARs). Despite its importance in tea cultivation, the mechanisms underlying AR development in tea remain unclear. In this study, we demonstrated the essential role of auxins in the initiation and progression of AR and established that the application of exogenous 1-naphthaleneacetic acid-enhanced AR formation in tissue-cultured seedlings and cuttings. Then, we found that the auxin-responsive transcription factor CsSPL9 acted as a negative regulator of AR development by reducing the levels of free indole-3-acetic acid (IAA) in tea plants. Furthermore, we identified CsGH3.4 as a downstream target of CsSPL9, which was activated by direct binding to its promoter. CsGH3.4 also inhibited AR development and maintained low levels of free IAA. Thus, these results revealed the inhibitory effect of the auxin-responsive CsSPL9-CsGH3.4 module on AR development by reducing free IAA levels in tea. These findings have significant theoretical and practical value for enhancing tea breeding practices.


Assuntos
Camellia sinensis , Regulação da Expressão Gênica de Plantas , Ácidos Indolacéticos , Proteínas de Plantas , Raízes de Plantas , Fatores de Transcrição , Ácidos Indolacéticos/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Raízes de Plantas/genética , Camellia sinensis/crescimento & desenvolvimento , Camellia sinensis/genética , Camellia sinensis/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Reguladores de Crescimento de Plantas/metabolismo , Ácidos Naftalenoacéticos/farmacologia , Plântula/crescimento & desenvolvimento , Plântula/genética , Plântula/metabolismo , Regiões Promotoras Genéticas
3.
Pharmacol Res ; 204: 107189, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38649124

RESUMO

Spinal cord injury (SCI) is a complex problem in modern medicine. Fibroblast activation and fibroscarring after SCI impede nerve recovery. Non-coding RNA plays an important role in the progression of many diseases, but the study of its role in the progression of spinal fibrosis is still emerging. Here, we investigated the function of circular RNAs, specifically antisense to the cerebellar degeneration-related protein 1 (CDR1as), in spinal fibrosis and characterized its molecular mechanism and pathophysiology. The presence of CDR1as in the spinal cord was verified by sequencing and RNA expression assays. The effects of inhibition of CDR1as on scar formation, inflammation and nerve regeneration after spinal cord injury were investigated in vivo and in vitro. Further, gene expression of miR-7a-5p and protein expression of transforming Growth Factor Beta Receptor II (TGF-ßR2) were measured to evaluate their predicted interactions with CDR1as. The regulatory effects and activation pathways were subsequently verified by miR-7a-5p inhibitor and siCDR1as. These results indicate that CDR1as/miR-7a-5p/TGF-ßR2 interactions may exert scars and nerves functions and suggest potential therapeutic targets for treating spinal fibrotic diseases.


Assuntos
Fibrose , MicroRNAs , RNA Circular , RNA Longo não Codificante , Transdução de Sinais , Traumatismos da Medula Espinal , Traumatismos da Medula Espinal/metabolismo , Traumatismos da Medula Espinal/genética , Traumatismos da Medula Espinal/fisiopatologia , Animais , MicroRNAs/genética , MicroRNAs/metabolismo , RNA Circular/genética , RNA Circular/metabolismo , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Medula Espinal/metabolismo , Medula Espinal/patologia , Proteínas Smad/metabolismo , Proteínas Smad/genética , Regeneração Nervosa , Feminino , Masculino , Receptor do Fator de Crescimento Transformador beta Tipo II/genética , Receptor do Fator de Crescimento Transformador beta Tipo II/metabolismo , Camundongos Endogâmicos C57BL , Camundongos , Recuperação de Função Fisiológica
4.
Nanotechnology ; 35(32)2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38306698

RESUMO

Two-dimensional transition metal dichalcogenide (TMDC) thin films have been extensively employed in microelectronics research. Molybdenum disulfide (MoS2), as one of prominent candidates of this class, has been applied in photodetectors, integrated electronic devices, gas sensing, and electrochemical catalysis, owing to its extraordinary optoelectronic, chemical, and mechanical properties. Synthesis of MoS2crystal film is the key to its application. However, the reported technology revealed several drawbacks, containing limited surface area, prolonged high-temperature environment, and unsatisfying crystallinity. In order to enhance the convenience of MoS2applications, there is a pressing need for optimized fabrication technology, which could be quicker, with a large area, with adequate crystallinity and heat-saving. In this work, we presented an ultraviolet laser-assisted synthesis technology, accomplishing rapid growth (with the growth rate of about 40µm s-1) of centimeter-scale MoS2films at room temperature. To achieve this, we self-assembled a displaceable reaction chamber system, coupled with krypton fluoride ultraviolet pulse laser. The laser motion speed and trajectory could be customized in the software, allowing the maskless patterning of crystal films. As application, we exhibited a photodetector with the integration of synthesized MoS2and lead sulfide colloidal quantum dots (PbS CQDs), displaying broadband photodetection from ultraviolet, visible to near-infrared spectrum (365-1550 nm), with the detectivity of 109-1010Jones, and the rising time of 0.2-0.3 s. This work not only demonstrated a high-process-efficiency synthesis of TMDC materials, but also has opened up new opportunities for ultraviolet laser used in optoelectronics.

5.
Molecules ; 29(8)2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38675571

RESUMO

Phyllanthus emblica is a natural medicinal herb with diverse bioactivities. Certain extracts from this herb have been confirmed to possess anti-glycolipid metabolic disorder activity. To further develop its utility value and explore its potential in combating glycolipid metabolic disorders, we designed a series of experiments to investigate the structure, antioxidant activity, and anti-glycolipid metabolic disorder activity of Phyllanthus emblica polysaccharides. In this study, we extracted and purified polysaccharides from Phyllanthus emblica and thoroughly analyzed their structure using various techniques, including NMR, methylation analysis, and surface-enhanced Raman spectroscopy. We investigated the hypolipidemic and anti-glycolipid metabolism disorder activity of Phyllanthus emblica polysaccharides for the first time utilizing oleic acid (OA) and advanced glycation end products (AGEs) as inducers. Additionally, the antioxidant activity of Phyllanthus emblica polysaccharides was assessed in vitro. These findings lay the groundwork for future investigations into the potential application of Phyllanthus emblica polysaccharides as an intervention for preventing and treating diabetes.


Assuntos
Antioxidantes , Phyllanthus emblica , Polissacarídeos , Phyllanthus emblica/química , Polissacarídeos/farmacologia , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Antioxidantes/farmacologia , Antioxidantes/química , Antioxidantes/isolamento & purificação , Glicolipídeos/química , Glicolipídeos/farmacologia , Glicolipídeos/isolamento & purificação , Produtos Finais de Glicação Avançada/metabolismo , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Animais , Ácido Oleico/química , Ácido Oleico/farmacologia , Humanos
6.
Appl Microbiol Biotechnol ; 107(7-8): 2403-2412, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36929192

RESUMO

Polyketides are a class of natural products with astonishing structural diversities, fascinating biological activities, and a versatile of applications. In polyketides biosynthesis, acyltransferases (ATs) are the 'gatekeeping' enzymes selecting the specific CoA-activated acyl groups as building blocks and transferring them onto the phosphopantetheine arm of acyl carrier proteins (ACPs) to enable the following condensation reactions to assemble the polyketide chain. Herein, the Art2 protein from aurantinins, a group of the antibacterial polyketides, is characterized in vitro as an AT that can load a CoA-activated succinyl unit onto the first ACP domain of Art17 (ACPArt17-1). In addition, another two proteins, GbnB and EtnB, involved in the biosynthesis of gladiolin and etnangien respectively, were traced by literature mining, homologous searching, and product structure analysis and then identified as functional succinyl-CoA ATs by the ACPArt17-1 assays. Taken together, by the assay method employing ACPArt17-1 as an acyl acceptor, we identified three ATs that can introduce a succinyl unit into the polyketide assembly line, which enriches the toolbox of polyketide biosynthetic enzymes and sets a stage for incorporating a succinyl unit into polyketide backbones in synthetic biological manners. KEY POINTS: • Three acyltransferases that are able to load ACP with a succinyl unit were characterized in vitro. • ACPArt17-1 can be used as an acceptor to assay succinyl-CoA AT from different polyketides. • The succinyl unit can be incorporated into polyketides assembly process.


Assuntos
Aciltransferases , Policetídeos , Aciltransferases/metabolismo , Policetídeos/metabolismo , Acil Coenzima A/metabolismo , Antibacterianos , Policetídeo Sintases/metabolismo
7.
J Environ Manage ; 344: 118516, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37413733

RESUMO

Centralized vs. decentralized sewage treatment is one of the key issues in the planning of rural sewage treatment (RST) in China due to the country's diverse regional characteristics. There are very limited comprehensive evaluation models for selecting regionally suitable schemes and facilities, particularly for national or provisional scale planning. As a scenario-based multi-attribute decision-making (MADM) issue, this paper develops a novel RST suitability evaluation model by integrating the multi-attribute analytic hierarchy process (AHP) with the technique for order preference by similarity to an ideal solution (TOPSIS). The suitability evaluation model sets up 3 small-centralized and 4 decentralized RST facilities as candidates and includes 12 evaluation indicators that cover economic cost, life cycle environmental impacts, technical features and operations management. Eight generic scenarios are classified for Chinese rural areas based on differences in three major characteristic factors, i.e., population density (PD), the economic development level (EDL), and topographic slope (TS). The universal evaluation results show that a centralized sewage treatment scheme is more suitable for areas with a high PD/high EDL/low TS, while a decentralized scheme is more suitable for areas with a low PD/low EDL/high TS. Sensitivity analysis shows that in regions with a high PD/low EDL, the indicator weight of the construction investment cost in the model has a great influence on the facility suitability ranking. However, in regions with a high PD/high EDL, the ranking is the most sensitive to the indicator weights of the global warming potential and sewage treatment effect. Furthermore, as a spatial decision issue, an RST suitability map of Hunan Province in China is produced at the county level of resolution, and the map is generally consistent with our field knowledge of several counties in Hunan Province. The presented evaluation framework can be integrated into environmental decision support systems in the future to help local and central governments, water utilities, design institutes and other stakeholders scientifically plan RST projects.


Assuntos
Meio Ambiente , Esgotos , Modelos Teóricos , China
8.
Phys Rev Lett ; 128(5): 052501, 2022 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-35179938

RESUMO

Efficient production of nuclear isomers is critical for pioneering applications, like nuclear clocks, nuclear batteries, clean nuclear energy, and nuclear γ-ray lasers. However, due to small production cross sections and quick decays, it is extremely difficult to acquire a significant amount of isomers with short lifetimes via traditional accelerators or reactors because of low beam intensity. Here, for the first time, we experimentally present femtosecond pumping of nuclear isomeric states by the Coulomb excitation of ions with the quivering electrons induced by laser fields. Nuclei populated on the third excited state of ^{83}Kr are generated with a peak efficiency of 2.34×10^{15} particles/s from a tabletop hundred-TW laser system. It can be explained by the Coulomb excitation of ions with the quivering electrons during the interaction between laser pulses and clusters at nearly solid densities. This efficient and universal production method can be widely used for pumping isotopes with excited state lifetimes down to picoseconds, and could be a benefit for fields like nuclear transition mechanisms and nuclear γ-ray lasers.

9.
Artigo em Inglês | MEDLINE | ID: mdl-35576246

RESUMO

A novel Gram-stain-positive, rod-shaped, non-motile bacterial strain, designated IM3328T, was isolated from a mud cellar which has been continuously used over hundreds of years for the fermentative production of Chinese strong-flavour baijiu. It is asporogenous, facultative anaerobic and does not exhibit catalase activity. Strain IM3328T can grow at pH 4.5-8.5 (optimum, pH 7.0), 15-45 °C (optimum, 37 °C), with 0-75% (w/v) ethanol with and 0-6% (w/v) NaCl. The API 50CH assay revealed that strain IM3328T can metabolize l-arabinose, d-ribose, d-xylose, d-glucose, d-fructose, d-mannose, N-acetylglucosamine, gluconate, methyl ß-d-pyranoside, methyl α-d-glucopyranoside, methyl α-d-glucopyranoside and raffinose among the 49 studied carbon sources. Lactic acid, acetic acid, ethanol, isopentanol and butyl acetate are he predominant metabolites in the fermentation broth of strain IM3328T when cultured in liquid de Man, Rogosa and Sharpe medium under micro-aerobic or anaerobic conditions. The polar lipids of strain IM3328T consist of diphosphatidylglycerol, phosphatidylglycerol, one unidentified phospholipid, two unidentified glycolipids and two unidentified lipids. The major cellular fatty acids (≥10%) consist of C16 : 0, C18:1 ω9c and summed feature 7. The cell wall contains ribose, glucose, galactose, lysine, alanine, glutamic acid and aspartic acid. The complete genome of strain IM3328T contains a circular chromosome of 1242019 bp with 1242 genes and 33 mol% G+C content. On the basis of the 16S rRNA gene phylogenetic tree, Lentilactobacillus senioris DSM 24302T (95.9% similarity), Lentilactobacillus rapi DSM 19907T (95.7% similarity) and Lentilactobacillus parabuchneri DSM 5707T (95.1% similarity) were chosen to compare with strain IM3328T to reveal the physiological differences. The low average nucleotide identity values (69.7-71.2%) between strain IM3328T and phylogenetically related reference strains demonstrated that this strain represents a novel species of the genus Lentilactobacillus, and the name Lentilactobacillus laojiaonis sp. nov. (type strain IM3328T=CGMCC 1.18832T=JCM 34630T) is proposed.


Assuntos
Ácidos Graxos , Lactobacillaceae , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Etanol , Ácidos Graxos/química , Fermentação , Humanos , Fosfolipídeos/química , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
10.
Plant J ; 101(1): 18-36, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31454118

RESUMO

The plant flavonoid dogma proposes that labile plant flavonoid carbocations (PFCs) play vital roles in the biosynthesis of proanthocyanidins (PAs). However, whether PFCs exist in plants and how PFCs function remain unclear. Here, we report the use of an integrative strategy including enzymatic assays, mutant analysis, metabolic engineering, isotope labeling and metabolic profiling to capture PFCs and demonstrate their functions. In anthocyanidin reductase (ANR) assays, an (-)-epicatechin conjugate was captured in protic polar nucleophilic methanol alone or methanol-HCl extracts. Tandem mass spectrum (MS/MS) analysis characterized this compound as an (-)-epicatechin-4-O-methyl (EOM) ether, which resulted from (-)-epicatechin carbocation and the methyl group of methanol. Acid-based catalysis of procyanidin B2 and B3 produced four compounds, which were annotated as two EOM and two (+)-catechin-4-O-methyl (COM) ethers. Metabolic profiling of seven PA pathway mutants showed an absence or reduction of two EOM ether isomers in seeds. Camellia sinensis ANRa (CsANRa), leucoanthocyanidin reductase c (CsLARc), and CsMYB5b (a transcription factor) were independently overexpressed for successful PA engineering in tobacco. The EOM ether was remarkably increased in CsANRa and CsMYB5b transgenic flowers. Further metabolic profiling for eight green tea tissues revealed two EOM and two COM ethers associated with PA biosynthesis. Moreover, an incubation of (-)-epicatechin or (+)-catechin with epicatechin carbocation in CsANRa transgenic flower extracts formed dimeric procyanidin B1 or B2, demonstrating the role of flavan-3-ol carbocation in the formation of PAs. Taken together, these findings indicated that flavan-3-ol carbocations exist in extracts and are involved in the biosynthesis of PAs of plants.


Assuntos
Flavonoides/metabolismo , Proantocianidinas/biossíntese , Camellia sinensis/genética , Camellia sinensis/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , NADH NADPH Oxirredutases/genética , NADH NADPH Oxirredutases/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
11.
J Virol ; 94(14)2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32404523

RESUMO

Anti-human immunodeficiency virus type 1 (anti-HIV-1) fusion peptides have been studied for nearly 2 decades, but few candidates have found useful clinical applications. One factor underlying the failure of such agents to reach the clinic is their poor pharmacokinetic properties, and many efforts have been made to overcome this problem. In this study, we modified C34, a peptide inhibitor of HIV-1 fusion, at its conserved glycosylation site using polyethylene glycols (PEGs) of different molecular weights. PEG40-NC, a conjugate of C34 and branched PEG 40 kDa (PEG40), which has been previously shown to improve the pharmacokinetic profiles of proteins, showed a significantly extended half-life (t1/2; 10.39 h in rats), which compensated for decreased in vitro activity (50% effective concentration [EC50] of 18.51 nM). PEG40-NC also showed a mechanism of action similar to that of C34. PEG40-NC monotherapy in acutely simian-human immunodeficiency virus (SHIV)-infected rhesus monkeys significantly suppressed viral load compared with a control treatment. Efficacy was linked to the extended half-life and lymphatic exposure conferred by attached PEG40. These results highlight the potential of further clinical investigations of PEG40-NC in combination with antiretroviral therapy or other anti-HIV agents.IMPORTANCE Poor pharmacokinetics have severely hindered the clinical use of anti-HIV peptides. Different small molecules, such as lipid, cholesterol, and small PEG, were designed to modify peptides to improve their pharmacokinetics. In this study, we incorporated large branched PEG to anti-HIV peptide and obtained a conjugate with extended half-life and improved in vivo efficacy. The strategy we developed in this study can also be applicable for the development of other peptide candidates.


Assuntos
Proteína gp41 do Envelope de HIV , Inibidores da Fusão de HIV , Infecções por HIV , HIV-1/metabolismo , Fragmentos de Peptídeos , Polietilenoglicóis/química , Síndrome de Imunodeficiência Adquirida dos Símios , Vírus da Imunodeficiência Símia/metabolismo , Animais , Proteína gp41 do Envelope de HIV/química , Proteína gp41 do Envelope de HIV/farmacocinética , Proteína gp41 do Envelope de HIV/farmacologia , Inibidores da Fusão de HIV/química , Inibidores da Fusão de HIV/farmacocinética , Inibidores da Fusão de HIV/farmacologia , Infecções por HIV/tratamento farmacológico , Infecções por HIV/metabolismo , Infecções por HIV/patologia , Humanos , Macaca mulatta , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/farmacocinética , Fragmentos de Peptídeos/farmacologia , Síndrome de Imunodeficiência Adquirida dos Símios/tratamento farmacológico , Síndrome de Imunodeficiência Adquirida dos Símios/metabolismo , Síndrome de Imunodeficiência Adquirida dos Símios/patologia
12.
Nanotechnology ; 32(1): 015701, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32942263

RESUMO

Monolayer MoS2 possesses good electron mobility, structural flexibility and a direct band gap, enabling it to be a promising candidate for flexible and wearable optoelectronic devices. In this article, the lateral monolayer MoS2 homojunctions were prepared by a nitrogen plasma selective doping technique. The monolayer MoS2 thin films were synthesized by chemical vapor deposition and characterized by photoluminescence, atom force microscope and Raman spectroscopy. The electronic and photoelectric properties of the lateral pn and npn homojunctions were discussed. The results showed that the rectifying ratio of the pn homojunction diode is ∼103. As a photodetector of pn homojunction, the optical responsivity is up to 48.5 A W-1, the external quantum efficiency is 11 301%, the detectivity is ∼109 Jones and the response time is 20 ms with the laser of 532 nm and the reverse bias voltage of 10 V. As a bipolar junction transistor of npn homojunction, the amplification coefficient reached ∼102. A controllable plasma doping technique, compatible with traditional CMOS process, is utilized to realize the monolayer MoS2 based pn and npn homojunctions, and it propels the potential applications of 2D materials in the electronic, optoelectronic devices and circuits.

13.
Mar Drugs ; 19(7)2021 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-34202523

RESUMO

Two new diterpenoids, hypoxyterpoids A (1) and B (2), and four new isocoumarin derivatives, hypoxymarins A-D (4-7), together, with seven known metabolites (3 and 8-13) were obtained from the crude extract of the mangrove-derived fungus Hypoxylon sp. The structures of the new compounds were elucidated on the basis of 1- and 2-dimensional (1D/2D) nuclear magnetic resonance (NMR) spectroscopic and mass spectrometric analysis. The absolute configurations of compounds 1, 2, 4, 5, and 7 were determined by comparison of experimental and calculated electronic circular dichroism (ECD) spectra, and the absolute configurations of C-4' in 6 and C-9 in 7 were determined by [Rh2(OCOCF3)4]-induced ECD spectra. Compound 1 showed moderate α-glucosidase inhibitory activities with IC50 values of 741.5 ± 2.83 µM. Compounds 6 and 11 exhibited DPPH scavenging activities with IC50 values of 15.36 ± 0.24 and 3.69 ± 0.07 µM, respectively.


Assuntos
Diterpenos/farmacologia , Fungos , Inibidores de Glicosídeo Hidrolases/farmacologia , Isocumarinas/farmacologia , Organismos Aquáticos , Diterpenos/química , Humanos , Concentração Inibidora 50 , Isocumarinas/química , Estrutura Molecular , Áreas Alagadas
14.
Proc Natl Acad Sci U S A ; 115(11): 2818-2823, 2018 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-29483275

RESUMO

Seven-carbon-chain-containing sugars exist in several groups of important bacterial natural products. Septacidin represents a group of l-heptopyranoses containing nucleoside antibiotics with antitumor, antifungal, and pain-relief activities. Hygromycin B, an aminoglycoside anthelmintic agent used in swine and poultry farming, represents a group of d-heptopyranoses-containing antibiotics. To date, very little is known about the biosynthesis of these compounds. Here we sequenced the genome of the septacidin producer and identified the septacidin gene cluster by heterologous expression. After determining the boundaries of the septacidin gene cluster, we studied septacidin biosynthesis by in vivo and in vitro experiments and discovered that SepB, SepL, and SepC can convert d-sedoheptulose-7-phosphate (S-7-P) to ADP-l-glycero-ß-d-manno-heptose, exemplifying the involvement of ADP-sugar in microbial natural product biosynthesis. Interestingly, septacidin, a secondary metabolite from a gram-positive bacterium, shares the same ADP-heptose biosynthesis pathway with the gram-negative bacterium LPS. In addition, two acyltransferase-encoding genes sepD and sepH, were proposed to be involved in septacidin side-chain formation according to the intermediates accumulated in their mutants. In hygromycin B biosynthesis, an isomerase HygP can recognize S-7-P and convert it to ADP-d-glycero-ß-d-altro-heptose together with GmhA and HldE, two enzymes from the Escherichia coli LPS heptose biosynthetic pathway, suggesting that the d-heptopyranose moiety of hygromycin B is also derived from S-7-P. Unlike the other S-7-P isomerases, HygP catalyzes consecutive isomerizations and controls the stereochemistry of both C2 and C3 positions.


Assuntos
Escherichia coli/metabolismo , Higromicina B/biossíntese , Fosfatos Açúcares/metabolismo , Vias Biossintéticas , Escherichia coli/enzimologia , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Heptoses/metabolismo , Higromicina B/química , Nucleosídeos de Purina/biossíntese , Nucleosídeos de Purina/química , Fosfatos Açúcares/química
15.
Proc Natl Acad Sci U S A ; 115(18): E4151-E4158, 2018 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-29678829

RESUMO

Tea, one of the world's most important beverage crops, provides numerous secondary metabolites that account for its rich taste and health benefits. Here we present a high-quality sequence of the genome of tea, Camellia sinensis var. sinensis (CSS), using both Illumina and PacBio sequencing technologies. At least 64% of the 3.1-Gb genome assembly consists of repetitive sequences, and the rest yields 33,932 high-confidence predictions of encoded proteins. Divergence between two major lineages, CSS and Camellia sinensis var. assamica (CSA), is calculated to ∼0.38 to 1.54 million years ago (Mya). Analysis of genic collinearity reveals that the tea genome is the product of two rounds of whole-genome duplications (WGDs) that occurred ∼30 to 40 and ∼90 to 100 Mya. We provide evidence that these WGD events, and subsequent paralogous duplications, had major impacts on the copy numbers of secondary metabolite genes, particularly genes critical to producing three key quality compounds: catechins, theanine, and caffeine. Analyses of transcriptome and phytochemistry data show that amplification and transcriptional divergence of genes encoding a large acyltransferase family and leucoanthocyanidin reductases are associated with the characteristic young leaf accumulation of monomeric galloylated catechins in tea, while functional divergence of a single member of the glutamine synthetase gene family yielded theanine synthetase. This genome sequence will facilitate understanding of tea genome evolution and tea metabolite pathways, and will promote germplasm utilization for breeding improved tea varieties.


Assuntos
Camellia sinensis/genética , Evolução Molecular , Duplicação Gênica , Genoma de Planta , Chá , Camellia sinensis/metabolismo
16.
Plant Dis ; 105(10): 3224-3230, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33507097

RESUMO

Matricaria chamomilla flower extract was used as a biocompatible material for synthesis of zinc oxide nanoparticles (ZnONPs). The synthesized NPs were evaluated for their antibacterial potential in vitro and in vivo against the Gram-negative bacterium Ralstonia solanacearum, which causes devastating bacterial wilt disease in tomato and other crops. Synthesized ZnONPs were further analyzed by UV-visible spectroscopy, Fourier transform infrared spectroscopy, x-ray diffraction, transmission electron microscopy, and scanning electron microscopy with energy-dispersive spectroscopy. The synthesized polydisperse ZnONPs were found to be in the size range of 8.9 to 32.6 nm, and at 18.0 µg ml-1 exhibited maximum in vitro growth inhibition of the pathogen R. solanacearum. Scanning electron microscopy analysis of affected bacterial cells showed morphological deformation such as disruption of the cell membrane and wall, and the leakage of cell contents. Results of in vivo studies also showed that application of ZnONPs to the artificially inoculated tomato plants with the pathogen R. solanacearum significantly enhanced the plant growth by reducing bacterial soil population and disease severity as compared with the untreated control. Biosynthesized ZnONPs could be an effective approach to control the bacterium R. solanacearum.


Assuntos
Matricaria , Nanopartículas , Ralstonia solanacearum , Solanum lycopersicum , Óxido de Zinco , Testes de Sensibilidade Microbiana , Óxido de Zinco/farmacologia
17.
FASEB J ; 33(10): 10859-10871, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31266356

RESUMO

Ischemic spinal cord injury (ISCI) results in the motor sensory dysfunction of the limbs below the injury site. In response to the injury, astrocytes develop into neuroprotective astrocytes [(neurotrophic reactive astrocytes (A2s)] to mitigate the damage. MicroRNA (miR)-21 can promote the development of neuroinflammation in previous studies. Our aim was to investigate the effect of miR-21 on its polarization. We used the abdominal aortic occlusion model in vivo. Immunohistochemistry was used to detect the distribution of A2s in the spinal cord. We used an oxygen glucose deprivation method to model astrocytes ischemia in vitro and tested proliferation, migration, and excitability of A2s using an 5-ethynyl -2'-deoxyuridine kit, wound scratch assay, and calcium-ion probe. After adjustment, we detected the model and target genes of A2s using PCR, Western blot, immunofluorescence, and chromatin immunoprecipitation. We demonstrated in vivo that naive astrocytes were transformed into A2s by ischemia. And in vitro miR-21, which can regulate the signal transducer and activator of transcription-3 pathway, can transform neurotoxic reactive astrocyte into A2. Moreover, we also verified the mechanism of A2s promoting synaptic formation and nerve growth. miR-21 is a switch to regulate the polarization of reactive astrocyte, and it promoted synapsis formation and nerites growth after acute ISCI.-Su, Y., Chen, Z., Du, H., Liu, R., Wang, W., Li, H., Ning, B. Silencing miR-21 induces polarization of astrocytes to the A2 phenotype and improves the formation of synapses by targeting glypican 6 via the signal transducer and activator of transcription-3 pathway after acute ischemic spinal cord injury.


Assuntos
Astrócitos/metabolismo , Glipicanas/metabolismo , MicroRNAs/metabolismo , Fator de Transcrição STAT3/metabolismo , Traumatismos da Medula Espinal/metabolismo , Sinapses/metabolismo , Animais , Astrócitos/citologia , Células Cultivadas , Feminino , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/genética , Neurogênese , Neurônios/citologia , Neurônios/metabolismo
18.
Nanotechnology ; 31(1): 015702, 2020 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-31514174

RESUMO

Low damaged doping of two-dimensional (2D) materials proves to be a significant obstacle in realizing fundamental devices such as p-n junction diodes and transistors due to its atom layer thickness. In this work, the defect formation energy and p-type conduction behavior of nitrogen plasma doping are investigated by first principle calculation. Low damaged substitutional p-type doping in MoS2 using low energy nitrogen plasma composed of N+ and N2 + is achieved by a novel toroidal magnetic field (TMF). The TMF helps to raise the concentration of N2 + ions at low RF power condition. The electrical characteristics of double-layer MoS2 field-effect transistors (FETs) clearly show an efficient p-type doping behavior. Atomic force microscope is applied to verify the slight damage in MoS2. X-ray photoelectron spectroscopy, photoluminescence and Raman spectroscopy confirm the effective p-type doping characteristic with weak damage. These findings provide a low damage technology for efficient carrier modulation of MoS2 and other homogeneous TMDC materials, which overcomes barriers in developing 2D electronic and optoelectronic devices.

19.
Planta Med ; 86(8): 571-578, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32325508

RESUMO

Hericium erinaceus is a very popular edible and medicinal mushroom used for the treatment of enervation and gastrointestinal diseases in Eastern Asia. Chemical investigation on the fruiting body of Hericium erinaceus led to the isolation of 4 new (1:  - 4: ) and 10 known meroterpenoids (5:  - 14: ). The structures of new compounds were determined via analysis of NMR and MS data in combination with chemical derivatization. The inhibitory activities of 1:  - 14: against α-glucosidase were evaluated using p-nitrophenyl-α-D-glucopyranoside, sucrose, or maltose as substrate. Compounds 6, 9, 11:  - 13: were demonstrated to show the α-glucosidase inhibitory activities. This work confirms the potential of H. erinaceus in the treatment of diabetes.


Assuntos
Agaricales , Basidiomycota , Carpóforos , alfa-Glucosidases
20.
Int Orthop ; 44(5): 995-1001, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32125464

RESUMO

PURPOSE: Only a few studies in the literature have reported on the outcome of ankle arthrodesis in haemophilia patients, and the optimal surgery technique for end-stage haemophilic ankle arthropathy remains controversial. The purpose of this study was to evaluate the results of ankle arthrodesis using the Ilizarov method in treating end-stage haemophilic ankle arthropathy. METHODS: Fourteen haemophilia patients with end-stage ankle arthropathy who underwent ankle arthrodesis using the Ilizarov method from December 2013 to May 2018 were enrolled in this study. The hospital day, fusion rate, complications, and functional outcomes were recorded and analyzed. Functional outcomes were evaluated according to the pre-operative and final follow-up of the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hind foot score, visual analog scale (VAS), and Medical Outcomes Short Form 12-item questionnaire score (SF-12) . RESULTS: All patients achieved bony fusion as confirmed by post-operative radiographs. The average time to fusion was 12.9 weeks (range, 10-17 weeks). Superficial pin track infection was observed in two patients, and subtalar arthritis was found in one patient. The mean AOFAS ankle-hind foot score, VAS score, physical component summary (PCS), and mental component summary (MCS) at final follow-up were significantly improved compared with the pre-operative data. All patients were satisfied with the surgery. CONCLUSIONS: Ankle arthrodesis using the Ilizarov method is a minimally invasive, effective, and safe surgical method and can be a viable option for hemophilia patients with end-stage ankle arthropathy.


Assuntos
Articulação do Tornozelo/cirurgia , Artrodese/métodos , Hemofilia A/complicações , Técnica de Ilizarov , Artropatias/cirurgia , Adulto , Humanos , Artropatias/etiologia , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento , Adulto Jovem
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